1. Field of the Invention
The present invention relates to a dental handpiece with a built-in electric motor for the drive of a dental treating implement which is arranged at one end of the handpiece. The implement is suppliable with a cooling medium through a cooling medium conduit in the handpiece; whereby the handpiece is detachably connectable with a current provider at its end which is distant from the implement, in which the current provider possesses electrical current supply contacts which are supplied with electrical current and which, upon the connection of the current provider with the handpiece, come into contact with current commutator or receiving contacts of the electric motor.
2. Discussion of the Prior Art
A handpiece of this type has become known from the disclosure of German Published Patent Appln. No. 12 50 053. In this presently known prior art handpiece, the current provider is equipped with a current supply cable, whereby a cooling medium supply conduit opens or discharges from the side of the current provider, and on whose discharging end there is attached a hose or tube forming the cooling medium conduit of the handpiece, and which extends exteriorly along the handpiece. Independently of the fact that this known handpiece can only be constantly employed in close proximity to a positionally fixed current supply source serving for supplying electrical current to the current supply cable; in general, only in a dental practice possessing a dental supply apparatus forming such an electrical current supply source, and as a consequence only utilizable in a restricted extent, because of the above-mentioned hose-plug connection it is not possible to effect a rapid automatic separation and connection of the cooling medium conduit of the handpiece and the cooling medium supply conduit of the current provider.
A handpiece which possesses to a different type of construction, and in which there lacks a cooling medium conduit in the handpiece, has become known from the disclosure of German Laid-Open Patent Appln. No. 31 22 065. In this known handpiece, the current supplier or provider consists of an input unit containing a battery. Besides the aspect that this known handpiece does not afford any capabilities for the cooling of the treating implement, also in this instance is there provided only a limited scope of utilization, inasmuch as any operation by means of a current provider other than a battery; for instance, an operation which in the given case would spare the battery, through a power supply apparatus supplied from electrical power mains and containing the positionally fixed electrical current supply source is, on the one hand, not possible because of the absence of a current provider adapted for this purpose, and on the other hand, because of the mentioned lack of cooling of the implement necessitated by the relatively high rotational speeds of the implement attainable during power-main supplied operation. In general, dental treatments require rotational speeds of the implement of 4,000 r.p.m. and, additionally, a constant cooling medium infeed to the tooth or the implement.